RT Journal Article SR Electronic T1 Achalasia cardia: dilatation or operation? JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 148 OP 149 DO 10.1136/gut.34.2.148 VO 34 IS 2 A1 J Spencer YR 1993 UL http://gut.bmj.com/content/34/2/148.abstract AB